Adds an addressed hex dump function to Rex::Text

Builds on to_hex_dump to add an address column

Useful when working with railgun:

mem = client.railgun.memread(address, 16)
puts Rex::Text.to_addr_hex_dump(mem, address)

004c3638    04 00 00 00 64 00 00 00 b8 f3 00 78 36 4c 00    ....d.....K.x6L.